The present invention relates to recursive effects devices, and more particularly to an intra-field recursive interpolator which interpolates between a current field and an opposite interlaced field only one field old.
In recursive video effects devices new video is mixed with old video to implement effects such as decay, picture trails, etc. This is accomplished by multiplying the old video, which is stored in a field store, by a decay constant between zero and unity. The new video is multiplied by the inverse of this decay constant and added to the old video as modified by the decay constant. A unity value for the decay constant yields a frozen picture, i.e., all old video, and a zero value yields no effect, i.e., all new video. In an interlaced television system the field of the stored video which is multiplied by the decay constant is combined with the corresponding field of the new video, i.e., with video which is two fields old. What is desired is the implementation of recursive effects which combines the stored video with video which is only one field old, i.e., the opposite interlaced field.